Digital Thermostats are designed for various heating and cooling HVAC systems. The system may be a single stage cooling or heating or perhaps a complex heat pump with dual stage cooling, heating, auxiliary heat, outsider air venting, etc. The thermostat detects various room and perhaps outside ambient conditions and based on these conditions activates certain relays to signal a service demand to the HVAC controller. These demand wires are typically color coded and, typically, are labeled (e.g., labels such as C, RX, O, B, RH, W, Y, G, A, L, T, E and Aux).
There are a variety of HVAC systems on the market today; there is no consistent naming convention when it comes to labeling control wires for such systems. Typically, a digital thermostat compatible with a particular HVAC system has either pre-assigned relay assignments or configuration options available, for instance, via the front panel. Relays in such systems are typically marked with a pre-assigned lettering to help the installer with installation. There remain a variety of 2, 3, 4, 5 or even 7 wires systems out there making the installation cumbersome and confusing.
What is needed is a system and method for configuring relays in HVAC system that is adaptable to HVAC systems having different relay naming conventions and different numbers of relays under control.